There have been a variety of technologies to expand the dynamic range of solid-state imaging devices.
A known method among them is, for example, the time-sharing system which composed of taking a plurality of images at certain intervals with varied sensitivities and then synthesizing the thus taken images into a single image.
Another known method is, for example, the space-sharing system which composed of providing light-receiving elements different from each other in sensitivity and allowing the light-receiving elements differing in sensitivity to capture a plurality of images and then synthesizing the thus captured images into a single image, thereby expanding the dynamic range. (See, PTLs 1 and 2, for example.)
Moreover, there is known the in-pixel memory system to expand the dynamic range. According to this system, each pixel is provided therein with a memory which stores charges overflowing from the photodiode so as to increase the amount of charges that can be stored in one exposure period. (See, PTL 3, for example.)